1. Field of Invention
This invention relates to weight measuring apparatus and more particularly the invention relates to a digital weight scale system comprising a scale mechanism apparatus for generating an electrical analog signal representing the weight on the scale and an analog to digital converting arrangement, a microprocessor and a display arrangement.
2. Description of the Prior Art
Weighing and computing scales must meet several stringent requirements for performance and cost. The scales must be accurate enough to satisfy public weights and measures authorities yet be available at reasonably affordable prices and perform their operations within a period of time which is convenient for sales transactions. In the past digital weighing and computing scales have typically been provided with the above types of apparatus and equipment and have performed the various functions required. In addition the scales have been provided with various control and protective features and apparatus to insure that the scale provides accurate indications of weights and at the same time cannot be improperly manipulated by an attendant to display an improper weight. For example, U.S. Pat. No. 3,709,309 granted to Williams Jr. et al Jan. 9, 1973 and Pat. No. 3,986,012 granted to Loshbough et al on Oct. 12, 1976 describe arrangements for accurately maintaining a scale at a zero indication when no weight is on the scale platform or platter. Pat. No. 4,159,521 granted to Hall et al on June 26, 1979 discloses various control arrangements to prevent improper operation of the scale in addition to the zero arrangement. Pat. No. 4,204,197 granted to Loshbough et al on May 20, 1980 shows still different arrangement for improving the operation of scales. Pat. No. 3,439,524 granted to Rogers on Apr. 22, 1969 shows an arrangement for compensating for the weight displayed by a scale at a relatively high percentage of the scale capacity. This arrangement however provides accurate correction at only such high weight and the correction introduce greater and greater errors the farther the weight is from the corrected weight.